TITLE : Spin localization and charge transport in hydrothermally synthesized 2H-MoS2

ABSTRACT :

Hydrothermal synthesis of molybdenum disulphide (MoS2) with varying S/Mo precursor ratio results in nanoparticle formation with 2H crystallographic phase, alongside a significant content of molybdenum reduced oxide (MoO3-x) as confirmed by Raman and XPS measurements. Three distinct paramagnetic defect centres are identified by low temperature electron paramagnetic resonance (EPR) measurements, with the spins localized around sulphur vacancy centres offering strongest signal. Oxygen vacancies present in the MoO3-x offers the longest spin dephasing time (7.19 microseconds), whereas the spins localized in Mo-antisites show fastest spin dephasing. Temperature dependent resistivity measurements disclose a transition from three dimensional variable range hopping (3D-VRH) to thermally activated transport (TAT), where transition temperature (Ttr) correlates with MoO3-x content and activation energy of TAT transport correlates to sample morphology. Annealing in an inert environment is found to improve sample crystallinity, enhance threshold energies of charge transport and homogeneity of the paramagnetic sites.

MEETING DETAILS :

Joining Link: events.php

Speaker: Prof. Debamalya Banerjee

Venue: A4 Conference Room, South Campus, IIT Mandi

Date and Time: July 6th, 2023, 10:30 AM